Regeneration of vas deferens after vasectomy

A total of 338 specimens obtained from 182 patients undergoing reversal of previous vasectomies have been studied. The major histologic features are sprouting of tubules and extravasation of sperm. Neo-tubules grow only from the proximal end of the divided vas and were seen in 136 specimens. Sperm were present in the neo-tubules in 61 specimens, but in the lumen of the proximal vas in 88 per cent of all patients. Extravasation of sperm had occurred from the neo-tubules in 64 specimens. In 57/154 patients operated on bilaterally at the same time, regeneration was unilateral. The conclusion from the analysis of factors responsible for this selectively proximal process is that sperm secretion was probably a major factor but was certainly not the only factor responsible.